The present invention relates to a silver halide color light-sensitive photographic material having high storage stability and capable of stably and rapidly releasing a photographically useful group during color development.
Various effects can be obtained in accordance with the types of photographically useful groups released during color development.
A photographically useful compound necessary during development is generally added to a developing solution (commonly, a compound is added to a replenisher to keep necessary concentration in running equilibrium).
When a photographically useful compound is added to a developing solution or to a replenisher, however, it sometimes loses its effect under the influence of long-term storage (storage or running of the replenisher).
To prevent this, it is possible to previously add a photographically useful compound to a light-sensitive material and achieve its effect during development. This method has the advantage that the effect can be achieved only in a necessary location, i.e., in a specific layer and its vicinity of a multilayered light-sensitive material. However, if a photographically useful compound is added in an active form to a light-sensitive material, the compound decomposes under the influence of heat, moisture, or oxygen when the light-sensitive material is stored before development. Consequently, no effect can be achieved during development. Furthermore, the decomposition product sometimes gives unpreferable photographic changes to the light-sensitive material. Therefore, this method is inapplicable depending on the type of compound.
One method of solving this problem is disclosed in Jpn. Pat. Appln. KOKOKU Publication No. (hereinafter referred to as JP-B-)4-73573. In this method, a photographically useful compound is added in a substantially inactive form (i.e., a photographically useful compound precursor) to a light-sensitive material by blocking its active group, and this precursor functions as an active photographically useful compound in a developing solution.
This JP-B-4-73573 achieves both rapid release of an active photographically useful compound from a precursor during development and high storage stability of a light-sensitive material. However, further improvements of the storage stability of a light-sensitive material are still being demanded. Additionally, the release of an active photographically useful compound uses a reaction with hydroxylamines in a developing solution. This results in large variations in the photographic properties due to variations in the concentration of the hydroxylamines.
Jpn. Pat. Appln. KOKAI Publication No. (hereinafter referred to as JP-A-)8-339058, whose corresponding U.S. application is now patented to U.S. Pat. No. 5,561,031, has disclosed a color reversal photographic element in which a non-light sensitive emulsion and a bleaching accelerator-releasing compound capable of releasing the bleaching accelerator by the reaction with the oxidized form of a developing agent, are added to a single same layer or a combined layers.
This is a superior method in that a bleaching accelerator (photographically useful compound) is released non-imagewise during color development. However, a nonsensitive emulsion is chemically fogged in a reversal bath (fogging step) before color development. Hence, the method cannot be used for a color negative light-sensitive material or color paper light-sensitive material using no reversal bath.
JP-A-63-175850 has disclosed a light-sensitive material which contains silver halide grains having fog nuclei on their surfaces or subsurfaces in a silver halide emulsion and also contains a bleaching accelerator (photographically useful compound) releasing coupler. This method is excellent in that it achieves both high aging stability and good desilvering characteristics of a light-sensitive material. However, silver halide grains having fog nuclei on their surfaces or subsurfaces coexist in a silver halide emulsion layer. This sometimes adversely affects the aging stability of a light-sensitive material depending on the type of silver halide emulsion.
Also, in this method silver halide grains having fog nuclei coexist in a silver halide emulsion layer, so a bleaching accelerator is released imagewise to some extent. Hence, the release amount and the like factor readily vary in accordance with property changes due to storage of the coexisting silver halide emulsion.
JP-A-2-5042 has disclosed a color reversal material containing a surface-fogged silver halide emulsion and a bleaching accelerator-releasing compound. Since this color reversal material is subjected to black-and-white development before color development, the fogged silver halide emulsion forms developed silver during color development, so no oxidized form of a developing agent can be formed. Consequently, no photographically useful group cannot be generated during color development.